This invention is specifically related to an improved means for operating an article transfer mechanism adapted for rapid, intermittent, reciprocating motion. In one particular application, the improvement of this invention is adapted for use with a takeout device for transferring glass articles from a glass-making machine to a conveyor.
In glass-making machines, a rotary table is provided with a multiplicity of stations supporting molds for receiving molten glass which is dropped as separate gobs into the molds at a specific station from above the table. The table is rapidly, intermittently rotated, or indexed, so that specific stations disposed along the perimeter of the table are moved swiftly and smoothly to specific, predetermined locations called stations. After the glass-making operation is completed, the glass article is removed from the mold at a takeout station where a takeout device grasps the article and transfers it to a location away from the table, such as a conveyor.
Prior art takeout devices include article-grasping jaws slidably mounted for linear, reciprocal movement toward and away from the rotating table. This type of device is usually operated pneumatically, with pressure being applied to cylinders to advance and retract the jaws mounted on slide rails between the article pickup and article drop-off positions.
Unfortunately, it is difficult to obtain smooth acceleration and deceleration between the extreme positions of prior takeout devices. The operational speed of prior glass-making machines was substantially limited due to the nonuniform acceleration/deceleration characteristics of the takeout device. This problem is increased by the fact that the reciprocating takeout device must be brought temporarily to a stop during the article pickup and article drop-off operations. The speed limitations caused by the prior takeout devices decreased the total production capacity and cost efficiency of prior machines.
Moreover, it is difficult to accurately position prior takeout devices at the desired locations and still provide a high-speed takeout device capable of operating smoothly and uniformly. Accurate positioning of the takeout device is particularly important in conjunction with a glass-making machine since improper location can result in destruction of the glass article by the article-gripping jaws.
In prior pneumatic systems, an arrangement of stop members can be devised to abut the takeout mechanism at appropriate locations. In this type of system the takeout mechanism physically contacts against the stop member, creating additional, detrimental machine vibrations and noise and generally detracting from the overall smoothness of operation of the glass-making system. Prior art devices significantly sacrifice one of the desired qualities of speed and smoothness of operation to obtain the other. This invention utilizes a rotary actuator and linkage, adapted to optimize both characteristics, to produce a dramatically smoother system capable of operating speeds substantially higher than the prior art systems.